a brine - usually salt & sugar in water - is aimed at making the meat more moist and juicy.

one can add 'stuff' to a brine for flavor.

pushing that, there's a marinade - which is aimed primarily at introducing flavor.

most brines do not include an acid component
many / most marinades do include an acid.

acid may be vinegar, fruit juices, wine, lots of liquids on the acid scale.

so what? valid question.

the process of "cooking" - typically by heat - causes changes to the structure of proteins.

interestingly enough, "acids" produce the same changes.

some tv chef once demonstrated you can "cook" fish at room temperature in a bowl of lemon juice. the acid makes the same protein changes as the heat. if you need a home proof, buy some salmon, cut in half, put one pc in oven, liberally douse other pc with lemon juice, observe results.

so.... vinegar & chicken -
first vinegar has a taste - and that'll show up in the finished product. wine vinegar, cider vinegar, balsamic, etc. all have their own flavor profiles.

second, it will denature aka start to cook the proteins. too much too long can produce a chunk of chicken that is tough/chewy on the outside.

in my experience a splash of vinegar does help with marinade flavor penetration. a really mild acid - such as buttermilk - can go overnight with good results.

Thank you so much for this!! I hate having to buy pre-cooked chicken because I don't know how to properly grill my own. I Googled "seasoned grilled chicken breasts" expecting to find some generic cooking site, but then I saw the result for Cooking for Engineers and immediately clicked it because I know I can trust your recipes. I've had enormous success with your English toffee and peanut butter cookie recipes before. THANK YOU!!

Excellent! I thought I would never buy boneless skinless breasts becuase the way they turned out before (hawaiian slipper to start with) until I saw this. With this method, it turned just the way as they serve in restaurants. Brining is the most important step. Apart from the rub you used, I sprinkled steak seasoning (from costco). My wife and I just loved it.

What if you use a charcoal grill? It seems that this recipe only mentions grilling using a gas grill.

I use a charcoal Weber. Should I use the direct method? Indirect method? How many briquets shoud I use? And how should I time it?

I would build a two stage fire. Start with a hot fire providing direct heat to sear, then move to a low fire to finish. I don't use briquettes - only hardwood charcoal which seems to vary from manufacturer to manufacturer quite a bit, so I can't really provide guidance on how much to use. Don't time, use a fast response digital meat thermometer and go by internal temperature instead.

Bobbie Flay talked about brining on his grilling show, but he used much more salt. (he didn't measure, of course, just poured salt in from the box but he poured in quite a bit and said, you want it salty. Don't worry, it won't make the meat too salty.
I love brining - it makes the meat so much more juicy and flavorful!

TASTY, TASTY, TASTY! Maybe a little less salt next time, but overall, WHAT A DIFFERENCE! Not dry in the slightest. An incredible transformation.

You sir are a genius. Cheapest frozen breast I could find, turned out as good as any I've had out. Without skin too. It's a miracle. - Will be replacing the spice rub with some Tikka / Tandoori / Cajun spice, but other than that, and reducing the salt a little. Other than that, simply perfect.

I just cooked chicken breasts for the first time I'm my life! I was very surprised as to how nice and juicy they turned out. Now, there is no excuse for anyone to cook dry chicken..haha
Thanks for the amazing website. I've been using it as a guide, as I recently am getting into cooking.

Btw, I used 600ml water, 15g salt for 4 hours. The cayenne overpowered the other flavors, but I like it spicy so that was fine